PROJECT SUMMARY/ABSTRACT Candidate. The Mentored Patient-Oriented Research Career Development Award (K23) will enable me to acquire the focused training necessary to become an independent and leading investigator in technology- based physical activity interventions among African American women and reduce their risks for many chronic diseases. To date, I have gained exceptional training experiences in behavior change theories, research methods, multiculturalism, and diversity across different adult populations. This foundation facilitates the next steps of my proposed training, namely, developing expertise on the central factors related to regular physical activity engagement among African American (AA) women, and the skills necessary for the development, implementation, and evaluation of smartphone app technology prevention and intervention research. The proposed training and research will prepare me to take a leadership role in technology-enhanced interventions targeting PA disparities. Proposed Research. Only 36% of African American (AA) women meet the national recommendation of 150 minutes per week of moderate-to-vigorous physical activity. Consequently, this group is disproportionally impacted by many associated disease conditions, including type 2 diabetes and cardiovascular disease. Research on physical activity disparity in this group indicates a triadic and reciprocal interaction between individual characteristics, social norms, and environmental factors. Smartphone application technology (e.g. apps) has been recommended as an innovative and low-burden platform to enhance theoretically driven approaches to promoting PA among AA women. This technology facilitates the development of effective, and scalable approaches delivered in real time and that can reach people in their daily environments. Moreover, this platform supports the development of innovative social networks for social support. Further, a counseling session intervention that helps AA women to develop an initial, individualized plan for PA before starting a PA program may help to increase levels of motivation for physical activity. This K-award applicant proposes an individually tailored, culturally relevant and smartphone delivered PA program including short text messages adapted from an effective internet-delivered intervention. The app program will contain activity monitoring features, educational videos, information on alternative and nearby environments, and a peer-to-peer chatroom to increase social support for PA behaviors in AA women compared to general wellness text messaging control condition.